My 14' has the 18" FP6 package wheels that came stock with 235/50-18 Pirelli Zero Neros. Looks like the time is beginning to draw near for some new rubber. I was thinking about going up in width to a 255/45 or a 245/50. I "believe" the rim is 8" wide. Any thoughts on my size choices? Also any suggestions for some new rubber that won't break the bank and get maybe at least 30k out of. Daily driver vehicle here.

My 14' has the 18" FP6 package wheels that came stock with 235/50-18 Pirelli Zero Neros. Looks like the time is beginning to draw near for some new rubber. I was thinking about going up in width to a 255/45 or a 245/50. I "believe" the rim is 8" wide. Any thoughts on my size choices? Also any suggestions for some new rubber that won't break the bank and get maybe at least 30k out of. Daily driver vehicle here.

Personally, the widest I'd go on the 18x8 rim is 245. That's not to say you couldn't fit a 255 on there, but I think the 255 might bulge a bit too much for my taste.

you dont want to go wider than a 235, a 245 wont put down the full contact patch and you'll be wasting money, Ask me how i know. The only 245 i would put on there would be something by nitto because they tend to run a hair on the narrow side.

Can you run 255 front / 275 rear on the same size rim, 19 x 9.5 all around?

Yes, 255 is probably as small as you would want to go, and 275 is the largest you would want to go, but it would work. That being said, there's no benefit at that point for a street car, you're basically just carrying extra weight in the front for no reason. For a road race car, i would argue that the slight stretch would stabilize the sidewall, so it could be beneficial there, but you're really getting knitty-gritty at that point.

Still though, i believe the initial topic was one of rotation. I would not, nor do i see any point in, rotating tires to have a 255 in the rear and 275 on the front of a semi-powerful RWD car. The car would just drive and turn all kinds of stupid.